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WHY COMPROMISE SPEED v ACCURACY? HAVE IT ALL PicoScope PicoScope 5442 PicoScope 5443 PicoScope 5444 Channels 4 4 4 Bandwidth All modes: 60 MHz 8 to 15-bit modes: 100 MHz 16-bit mode: 60 MHz 8 to 15-bit modes: 200 MHz 16-bit mode: 60 MHz Sampling rate - real time 1 GS/s (8-bit mode) Buffer memory (8-bit) * 32 MS 128 MS 512 MS Buffer memory (≥ 12-bit)* 16 MS 64 MS 256 MS Resolution (enhanced)** 8 bits, 12 bits, 14 bits, 15 bits, 16 bits Hardware resolution + 4 bits Signal Generator Function generator or AWG 2 Channel models also available * Shared between active channels ** Maximum resolution is limited on the lowest voltage ranges: ±10 mV = 8 bits • ±20 mV = 12 bits. All other ranges can use full resolution. FLEXIBLE RESOLUTION OSCILLOSCOPE ALL MODELS INCLUDE PROBES, FULL SOFTWARE AND 5 YEAR WARRANTY. SOFTWARE INCLUDES MEASUREMENTS, SPECTRUM ANALYZER, SDK, ADVANCED TRIGGERS, COLOR PERSISTENCE, SERIAL DECODING (CAN, LIN, RS232, I²C, I²S, FLEXRAY, SPI), MASKS, MATH CHANNELS, ALL AS STANDARD, WITH FREE UPDATES. www.picotech.com/PS256 Design solution to reduce antenna effects There are several design solutions to reduce antenna effects. The routing options mean breaking signal wires and route the signal to upper metal layers by jumper insertion. All the metal being etched is not connected to a gate until the last metal layer is etched. One can also use dummy transistors by adding extra gates to reduce the capacitance ratio, but there may be reverse antenna effects. Another solution is to connect reverse biased diodes to the gate of transistor (during normal circuit operation, the diode does not affect functionality). Alternatively, after placement and route, designers could connect diodes only to those layers with antenna violations. One diode can be used to protect all input ports that are connected to the same output ports. Jumper insertion is the most effective method of avoiding antenna-effect problems while diode insertion can repair the remaining antenna problems. Jumper insertion A jumper is a forced layer change from one metal layer to another, and then back to the same layer. Jumper insertion breaks up a long wire so that the wire connected to the gate input is shorter and less capable of collecting charge, as shown in figure 2. It should be noted that the location where we are putting the jumper is very important. We have to put the jumper in such a way so as to decrease the length of the route. Figure 3 shows two nets with the same separation between the input and output pins, but slightly different jumper locations. The first one has no antenna violation but the second one is having Antenna violation. This example shows that antenna violations can be avoided through the use of jumpers (also known as “bridges”). A jumper directs the net to a higher metal layer before descending again. In the process of metallization, the pin is connected to a small amount of wire area, except on the highest layer, avoiding any antenna problem below that layer. Diode insertion As shown in figure 4, diode insertion near a logic gate input pin on a net provides a discharge path to the substrate so that built-up charges cannot damage the transistor gate. Using diodes, we are actually providing a discharge path for the extra ions that accumulates on the metal through the substrate. Unfortunately, diode insertion increases cell area and slows timing due to the increase of logic gate input load. Moreover, diode Figure 2 Figure 3 www.electronics-eetimes.com Electronic Engineering Times Europe November 2013 37


EETE NOV 2013
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